/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hanbang.qzzds.view.widget.slidingtab;

import android.content.Context;
import android.graphics.Typeface;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.SparseArray;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;
import android.widget.TextView;

/**
 * To be used with ViewPager to provide a tab indicator component which give
 * constant feedback as to the user's scroll progress.
 * <p/>
 * To use the component, simply add it to your view hierarchy. Then in your
 * {@link android.app.Activity} or {@link android.support.v4.app.Fragment} call
 * {@link #setViewPager(ViewPager)} providing it the
 * ViewPager this layout is being used for.
 * <p/>
 * The colors can be customized in two ways. The first and simplest is to
 * provide an array of colors via {@link #setSelectedIndicatorColors(int...)}.
 * The alternative is via the
 * {@link com.google.samples.apps.iosched.ui.widget.SlidingTabLayout.TabColorizer}
 * interface which provides you complete control over which color is used for
 * any individual position.
 * <p/>
 * The views used as tabs can be customized by calling
 * {@link #setCustomTabView(int, int)}, providing the layout ID of your custom
 * layout.
 */
public class SlidingTabLayout extends HorizontalScrollView {
    /**
     * 允许完全控制选项卡的颜色绘制布局
     * .
     */
    public interface TabColorizer {

        /**
         * @return 返回时使用的颜色指标 {@code position} is selected.
         */
        int getIndicatorColor(int position);

    }

    private static final int TITLE_OFFSET_DIPS = 24;
    private static final int TAB_VIEW_PADDING_DIPS = 16;
    private static final int TAB_VIEW_TEXT_SIZE_SP = 12;

    private int mTitleOffset;

    private int mTabViewLayoutId;
    private int mTabViewTextViewId;
    // 平均布局
    private boolean mDistributeEvenly = true;

    private ViewPager mViewPager;
    private SparseArray<String> mContentDescriptions = new SparseArray<String>();
    private ViewPager.OnPageChangeListener mViewPagerPageChangeListener;

    // 下面de线
    private final SlidingTabStrip mTabStrip;

    public SlidingTabLayout(Context context) {
        this(context, null);
    }

    public SlidingTabLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        // Disable the Scroll Bar
        setHorizontalScrollBarEnabled(false);
        // Make sure that the Tab Strips fills this View
        setFillViewport(true);

        mTitleOffset = (int) (TITLE_OFFSET_DIPS * getResources()
                .getDisplayMetrics().density);

        mTabStrip = new SlidingTabStrip(context);
        addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    }

    /**
     * Set the custom
     * to be used.
     * <p/>
     * 如果你只需要简单的custmisation然后您可以使用 {@link #setSelectedIndicatorColors(int...)}
     * 达到类似的效果。
     */
    public void setCustomTabColorizer(TabColorizer tabColorizer) {
        mTabStrip.setCustomTabColorizer(tabColorizer);
    }

    /*
     * 设置均匀分配
     */
    public void setDistributeEvenly(boolean distributeEvenly) {
        mDistributeEvenly = distributeEvenly;
    }

    /**
     * 设置颜色用于显示选中的选项卡。这些颜色被当作一个圆形阵列。 提供一种颜色将意味着所有的标签都表示相同的颜色
     */
    public void setSelectedIndicatorColors(int... colors) {
        mTabStrip.setSelectedIndicatorColors(colors);
    }

    /**
     * Set the {@link ViewPager.OnPageChangeListener}.
     * When using
     * {@link com.google.samples.apps.iosched.ui.widget.SlidingTabLayout} you
     * are required to set any
     * {@link ViewPager.OnPageChangeListener} through
     * this method. This is so that the layout can update it's scroll position
     * correctly.
     *
     * @see ViewPager#setOnPageChangeListener(ViewPager.OnPageChangeListener)
     */
    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
        mViewPagerPageChangeListener = listener;
    }

    /**
     * 设置自定义布局选项卡视图
     *
     * @param layoutResId 布局的id
     * @param textViewId  id of the {@link TextView} in the inflated view
     */
    public void setCustomTabView(int layoutResId, int textViewId) {
        mTabViewLayoutId = layoutResId;
        mTabViewTextViewId = textViewId;
    }

    /**
     * Sets the associated view pager. Note that the assumption here is that the
     * pager content (number of tabs and tab titles) does not change after this
     * call has been made.
     */
    public void setViewPager(ViewPager viewPager) {
        mTabStrip.removeAllViews();

        mViewPager = viewPager;
        if (viewPager != null) {
            viewPager.setOnPageChangeListener(new InternalViewPagerListener());
            populateTabStrip();
        }
    }

    /**
     * Create a default view to be used for tabs. This is called if a custom tab
     * view is not set via {@link #setCustomTabView(int, int)}.
     */
    protected TextView createDefaultTabView(Context context) {
        TextView textView = new TextView(context);
        textView.setGravity(Gravity.CENTER);
        textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, TAB_VIEW_TEXT_SIZE_SP);
        textView.setTypeface(Typeface.DEFAULT_BOLD);
        textView.setLayoutParams(new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT));

        TypedValue outValue = new TypedValue();
        textView.setBackgroundResource(outValue.resourceId);

        int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources()
                .getDisplayMetrics().density);
        textView.setPadding(padding, padding, padding, padding);

        return textView;
    }

    public void populateTabStrip() {
        if (mViewPager != null) {
            final PagerAdapter adapter = mViewPager.getAdapter();
            final OnClickListener tabClickListener = new TabClickListener();

            for (int i = 0; i < adapter.getCount(); i++) {
                View tabView = null;
                TextView tabTitleView = null;

                if (mTabViewLayoutId != 0) {
                    // If there is a custom tab view layout id set, try and
                    // inflate
                    // it
                    tabView = LayoutInflater.from(getContext()).inflate(
                            mTabViewLayoutId, mTabStrip, false);
                    tabTitleView = (TextView) tabView
                            .findViewById(mTabViewTextViewId);
                }

                if (tabView == null) {
                    tabView = createDefaultTabView(getContext());
                }

                if (tabTitleView == null && TextView.class.isInstance(tabView)) {
                    tabTitleView = (TextView) tabView;
                }

                if (mDistributeEvenly) {
                    LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView
                            .getLayoutParams();
                    lp.width = 0;
                    lp.weight = 1;
                }

                tabTitleView.setText(adapter.getPageTitle(i));
                tabView.setOnClickListener(tabClickListener);
                String desc = mContentDescriptions.get(i, null);
                if (desc != null) {
                    tabView.setContentDescription(desc);
                }

                mTabStrip.addView(tabView);
                if (i == mViewPager.getCurrentItem()) {
                    tabView.setSelected(true);
                }
            }
        }
    }

    public void setContentDescription(int i, String desc) {
        mContentDescriptions.put(i, desc);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        if (mViewPager != null) {
            scrollToTab(mViewPager.getCurrentItem(), 0);
        }
    }

    private void scrollToTab(int tabIndex, int positionOffset) {
        final int tabStripChildCount = mTabStrip.getChildCount();
        if (tabStripChildCount == 0 || tabIndex < 0
                || tabIndex >= tabStripChildCount) {
            return;
        }

        View selectedChild = mTabStrip.getChildAt(tabIndex);
        if (selectedChild != null) {
            int targetScrollX = selectedChild.getLeft() + positionOffset;

            if (tabIndex > 0 || positionOffset > 0) {
                // If we're not at the first child and are mid-scroll, make sure
                // we obey the offset
                targetScrollX -= mTitleOffset;
            }

            scrollTo(targetScrollX, 0);
        }
    }

    private class InternalViewPagerListener implements
            ViewPager.OnPageChangeListener {
        private int mScrollState;

        @Override
        public void onPageScrolled(int position, float positionOffset,
                                   int positionOffsetPixels) {
            int tabStripChildCount = mTabStrip.getChildCount();
            if ((tabStripChildCount == 0) || (position < 0)
                    || (position >= tabStripChildCount)) {
                return;
            }

            mTabStrip.onViewPagerPageChanged(position, positionOffset);

            View selectedTitle = mTabStrip.getChildAt(position);
            int extraOffset = (selectedTitle != null) ? (int) (positionOffset * selectedTitle
                    .getWidth()) : 0;
            scrollToTab(position, extraOffset);

            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageScrolled(position,
                        positionOffset, positionOffsetPixels);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            mScrollState = state;

            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageScrollStateChanged(state);
            }
        }

        @Override
        public void onPageSelected(int position) {
            if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
                mTabStrip.onViewPagerPageChanged(position, 0f);
                scrollToTab(position, 0);
            }
            for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                mTabStrip.getChildAt(i).setSelected(position == i);
            }
            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageSelected(position);
            }
        }

    }

    private class TabClickListener implements OnClickListener {
        @Override
        public void onClick(View v) {
            for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                if (v == mTabStrip.getChildAt(i)) {
                    mViewPager.setCurrentItem(i);
                    return;
                }
            }
        }
    }

}
